Diagnostic tests such as MRIs, CT scans and angiograms are routinely used because they provide important information about many diseases or injuries and can help in diagnosis and treatment. In many cases, the use of a contrast dye is necessary to enhance these tests, but sometimes these dyes can either lead to kidney problems, or cause problems in patients with kidney disease. There are two rare but serious disorders associated with contrast dyes and the kidneys: contrast induced nephropathy (CIN) and nephrogenic systemic fibrosis (NSF).
What is Contrast Induced Nephropathy (CIN)?
CIN is a rare disorder and occurs when kidney problems are caused by the use of certain contrast dyes. In most cases contrast dyes used in tests, such as CT (computerized tomography) and angiograms, have no reported problems. About 2 percent of people receiving dyes can develop CIN. However, the risk for CIN can increase for people with diabetes, a history of heart and blood diseases, and chronic kidney disease (CKD). For example, the risk of CIN in people with advanced CKD (glomerular filtration rate (GFR) below 30 mL/min/1.73m2), increases to 30 to 40 percent. The risk of CIN in people with both CKD and diabetes is 20 to 50 percent.
CIN is associated with a sharp decrease in kidney function over a period of 48-72 hours. The symptoms can be similar to those of kidney disease, which include feeling more tired, poor appetite, swelling in the feet and ankles, puffiness around the eyes, or dry and itchy skin. In many cases, CIN is reversible and people can recover. However, in some cases, CIN can lead to more serious kidney problems and possible heart and blood vessel problems.
What is Nephrogenic Systemic Fibrosis (NSF)?
NSF is a rare but serious disease affecting skin and other organs that has been found in some patients with advanced CKD after exposure to gadolinium-containing contrast dyes that are used in magnetic resonance imaging (MRI). NSF appears to affect about 4 percent of patients with advanced CKD. People with acute kidney injury (AKI) are also at higher risk. NSF has not been reported in people with mild kidney damage or normal kidney function.
NSF can be painful, debilitating, or even fatal. Symptoms and signs of NSF can include burning and itching of the skin, red or dark patches on the skin, joint stiffness, or muscle weakness. The disease can develop within 24 hours up to around 3 months.
MRIs are routinely used in patients to visualize internal organs and limbs to help detect and monitor many different diseases or injuries. Contrast dyes are often used during MRI to enhance the images obtained, and these dyes contain an element called gadolinium. In people with CKD, the kidneys are not able to filter out wastes, drugs and toxins the way they normally should. In advanced CKD, the excretion of gadolinium-containing contrast dyes used in MRIs is slower than in people with normal kidney function. This delay in excretion is thought to be one the main reasons why NSF may happen.
How can I reduce my risk for CIN and NSF?
- Know your GFR and if you have CKD. If you do not know your GFR, you can ask your doctor or healthcare professional. Your kidney function is estimated by the glomerular filtration rate, or eGFR.
- Tell all of your healthcare professionals about your GFR and CKD, especially if a diagnostic test such as a CT scan, MRI or angiogram has been ordered. Talk to the doctor ordering the diagnostic test. You can also ask to talk to the radiologist, radiology technician and nurse.
- If you need to have a CT scan, angiogram or MRI:
- Ask about your risk for NSF and CIN, based any risk factors you might have:
CIN Risk Factors
NSF Risk Factors
Use of CT scan or angiography with contrast dye, and one or more of the following:
- Heart and blood vessel problems
- Older age
Use of MRI with gadolinium -based contrast dye, and one of the following:
- Advanced kidney disease (GFR below 30 mL/min/1.73m2)
- Discuss the need for a contrast agent with your healthcare professional.
- Ask about alternatives such as a test without contrast, if feasible.
- If any of these tests with contrast dyes are necessary, ask about precautions that will be taken, including:
- Making sure to follow any instructions before, during or after the procedure, for example drinking fluids so you are not dehydrated.
- Asking about avoiding certain contrast dyes because of the risk of developing NSF or CIN.
- Allowing sufficient time for elimination of contrast dye before re-administering.
- Avoiding repeated or higher doses of contrast dye.
- Performing long-term monitoring for CIN or NSF after a diagnostic test.
- Know the signs and symptoms of CIN and NSF:
- Feeling more tired
- Poor appetite
- Swelling in the feet and ankles
- Puffiness and swelling around the eyes
- Dry and itchy skin
- Burning, itching, swelling, scaling, hardening and tightening of the skin
- Red or dark patches on the skin
- Stiffness in joints with trouble moving, bending or straightening the arms, hands, legs or feet
- Pain in the hip bones or ribs; or muscle weakness
- Contact your healthcare professional immediately if you experience any of these symptoms.
Can NSF and CIN be treated?
There are no proven treatments for NSF and CIN, but symptoms may gradually improve over time. New medications are showing promising results but prevention remains key.
There are benefits to undergoing these procedures. The benefits, however, should outweigh the risks associated with the use of contrast dye. These contrast dyes have helped in the diagnosis and treatment of many patients with various diseases and injuries, so there is also a risk of not doing these procedures.
If you would like more information, please contact us.
© 2015 National Kidney Foundation. All rights reserved. This material does not constitute medical advice. It is intended for informational purposes only. Please consult a physician for specific treatment recommendations.